The present invention relates to semiconductor device packages and more particularly to packages that include at least two series-connected diodes.
Very fast diodes are needed for continuous mode power factor correction (PFC). Also, in continuous mode PFC high voltage diodes, e.g., 600V or more, are desirable. However, as illustrated by FIG. 1, due to relatively slower reverse recovery time at higher voltage ratings, a diode having a high voltage rating suffers from relatively slower recovery time.
To overcome the above-noted disadvantages, a semiconductor device package according to the present invention includes at least two series-connected diodes of matched or similar voltage rating. Each individual diode is preferably rated for a relatively lower voltage application than would be necessary for a diode in a given continuous mode PFC application. However, the combination of the two series-connected diodes provides the desired voltage rating. Advantageously, the series-connected diodes exhibit better speed than a single diode of similar or identical voltage rating.
One aspect of the present invention the series-connected diodes are housed in a standard power package such as but not limited to a TO-220, D2 pak, TO220FP, TO297, etc. which does not include internal insulation. This type of package is often used to house a switching device such as a MOSFET or an IGBT. A conventional package includes three parallel leads, one of which (usually the center lead) may be integral with a conductive pad. In the present invention, the conductive pad of the package is used to connect an anode of one diode to the cathode of another diode in order to connect the two in series. The free electrode of each of the diodes is then connected by a wire bond to a respective free external lead of the package. Thus, according to the present invention, the lead that is integral with the conductive pad of the package (usually the center lead) may be used as a tap, while the other two leads can be used as respective connection terminals of the series-connected diodes.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.